How do flags and scopes fields work with multicasting?

A.
A scope is used for transient addresses, and flags are used to distinguish between local and
global groups.

B.
Flags are used with the prefix, and a scope is added to the group identifier.

C.
Flags are used for transient addressed, and a scope is used to distinguish between local and
global groups.

D.
Flags and scope fields work only with anycasting.

Explanation:
The flags field is 4 bits in length, and the first three bits are reserved and not yet assigned. The
fourth bit is the T bit, (RFC 2460) and used to determine if whether the multicast address is
permanent (well-known) or temporary (transient). Scoping is used to control the destination groups
to receive the message.
The following is the coding of the scope field in the multicast header, as per RFC 2373, the scope

is a 4-bit value, and the values are (in Hex):
0 reserved 1 node-local scope 2 link-local scope 3 (unassigned) 4 (unassigned) 5 site-local scope
6 (unassigned) 7 (unassigned) 8 organization-local scope 9 (unassigned) A (unassigned) B
(unassigned) C (unassigned)
D (unassigned) E global scope F reserved
Incorrect Answers:
A: These statements are incorrect.
B: These statements are incorrect.